Scanner and Class Files

My dad's scanner will not work after a reboot unless he reinstalls it, and then it still goes away after every reboot. It is a USB printer/scanner combo and the printer always works, but the system won't find the scanner without reinstalling every time! It will show in device manager, but can't communicate.
While installing, he always gets this error during the final part when it says "Completeing the installation process..." The error says:
"Unable to start the application... the class files could not be loaded. Catastrophic failure "
He has SP1 (it did this before SP1 as well), and all the newest drivers. It has done this with at least 3 different combos, as he thought they were bad units originally. The software also loads without the error on another computer at work. Any ideas?

 

I downloaded the Java to fix the class files error, but the scanner is still disappearing. Help.